| upper motor neuron | Clinical term indicating those neuron's of the motor cortex that contribute to the formation of the pyramidal or corticospinal and corticobulbar tracts, as distinguished from the lower motor neuron's innervating the skeletal muscles. Although not motor neuron's in the strict sense, these cortical neuron's became colloquially classified as motor neuron's because their stimulation produces movement and their destruction causes severe disorders of movement. See: motor neuron, motor cortex. (05 Mar 2000) |
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| upper motor neuron lesion | Injury to cerebral descending (corticonuclear) fibres above the brainstem or spinal motor nerve nucleus. Synonym: upper motor neuron lesion. (05 Mar 2000) |
| focal motor seizure | A simple partial seizure with localised motor activity. (05 Mar 2000) |
| lower motor neuron | Clinical term used to indicate the final motor neuron's that innervate the skeletal muscles; distinguished from upper motor neuron's of the motor cortex that contribute to the pyramidal or corticospinal tract. See: motor neuron. (05 Mar 2000) |
| lower motor neuron dysarthria | Dysarthria caused by dysfunction of the motor nuclei and the lower pons or medulla, or other neural connections, central and peripheral to the muscles of articulation. (05 Mar 2000) |
| lower motor neuron lesion | Injury to motor cells in the brainstem or spinal cord, or of the axons derived from them. (05 Mar 2000) |